Cryptography is used to share information among permitted parties while preventing access by undesired third parties. Cryptography is particularly useful in computer communication networks because information is often sent over untrusted networks and computers have the processing power to perform complex cryptographic algorithms. Symmetric encryption involves the use of a key shared by each of the permitted parties. The same symmetric key may be used for both encryption and decryption. Asymmetric encryption involves the use of a pair of keys, where one key is kept private and the other key is known publically. Hybrid encryption involves the combination of symmetric and asymmetric encryption.
Although symmetric, asymmetric, and hybrid encryption algorithms are known, most computer users do not make use of existing encryption systems. Computer users often communicate and send files or other data objects in unencrypted form leaving them vulnerable to privacy leaks and identity theft. For many users, existing cryptographic systems are confusing and cumbersome. Users may also be overwhelmed at the prospect of keeping track of numerous cryptographic keys, yet are reluctant to trust third parties or servers with the cryptographic keys.
Modern communications services do not have a secure infrastructure. Data may be routed along various pathways, possibly including foreign countries, without a user knowing which route is taken. Wireless communications may be easily intercepted. With the advent of cloud computing, services traditionally provided by trusted servers may now be farmed out to virtual machines which could be physically located anywhere.